Bk1

I am currently running my SDA 2B’s with an Adcom GFA 545. Beautiful soundstage and detail with most music. The only issue is classical, pianos don’t sound like pianos, and the music just seems to be missing that oomp? Someone has a B&K EX442 Sonata for sale on eBay for $550. Do you think this will help, or would money spent on a better preamp make more sense? Do you think this is a fair price?